Preheat oven to 325 degrees.,Cream butter and sugar together.,Beat in eggs, one at a time, until incorporated.,Sift flour, baking powder and salt together and fold into mixture.,______,Pour into well-buttered tube pan or into small loaf pans and bake 1 1/2 to 2 hours or until inserted cake tester comes out clean.,Allow to cool somewhat and remove from pan.,Glaze while still warm with confectioners' sugar-and- water icing to which a little grated lemon rind has been added.